iboats.com
Recruit
- Joined
- Apr 5, 2011
- Messages
- 4
Over the past 8 years I have probably read pleas for help from tens of thousands of people who have problems with their outboards. Most of these problems could have been rather quickly diagnosed and repaired if the user had prepared and equipped him/herself to troubleshoot and then used a logical approach to diagnosis.
Users are not prepared if:
- They don't understand how the engine works, what parts are involved, what they look like and where they are.
- They don't have diagnostic tools.
- They don't use a logical approach to diagnosis.
Here is a typical scenario. John Doe's outboard won't start. He turns the key and the engine goes "click" and does nothing else. All other electrics on his boat work.
So he buys a new battery. $70. Still just clicks, but it changed the weight of his bank account. So he buys a new starter. $200. Bank account gets lighter. Must be the solenoid.
New solenoid. $50.
So now John is $320 down and his outboard still won't start. Neighbor Joe comes over to see what is causing the string of colorful profanity spewing from John's garage. John spills the beans.
"Okay", says Joe, "Where's your manual?" John confesses that he "can't afford" a manual.
"You could have bought ten manuals for what you have spent, John. Well, start systems are all pretty similar. This looks a lot like mine. Let's get out your multimeter." John "can't afford" a multimeter and doesn't know how to use one anyway.
Joe goes home and gets his multimeter. He measures battery voltage: 12.6 volts. He asks John to try the starter. Voltage drops to 12.2 volts when John turns the key. "That is too little drop," says Joe.
"If the starter is getting current it should drop to between 9 and 11 volts. Let's see what you have at the solenoid." Joe puts his meter lead on the input to the solenoid from the battery.
"Try it now," he says. John turns the key, the solenoid clicks, as usual. "Twelve point six and twelve point two. That should drop to around 9 or 10 volts when you engage the starter. Let's try it at the starter." Joe moves his lead to the input terminal on the starter. They get exactly the same readings as at the solenoid.
"Rats!" says John. "I got another bad starter. I'll take it out and go get a good one." "Hold on a minute", says Joe. "Let me show you something. Notice that I have kept the ground lead from my meter on the negative terminal of the battery, not on the engine block. Now I move it to the engine block and my meter suddenly says zero with the starter not engaged and about half a volt when you turn the key. The starter is actually dropping that half volt, but the other 12.1 volts is getting dropped between the battery negative terminal and the engine block. Where is the negative cable from the battery attached to the engine?"
They find the negative cable from the battery bolted to the steel bypass cover on the block. Joe puts his positive meter lead on the block and the negative lead on the lug on the battery cable. It reads zero. "Try her now," says Joe. John turns the key and the meter reading jumps to 12.1 volts.
"Bingo!", says Joe. "This connection is bad. Let's take it off and clean it."
Five minutes later the engine springs to life. Cost? Zero bucks.
John wasn't prepared. He didn't have a manual, he didn't have a diagnostic tool, a multimeter, and didn't know how to use it. He did not apply logic to his approach.
One of my favorite expert helpers on the iboats technical forums is Steelspike. He is very fond of saying that, "Anyone who works on an outboard without a manual has a fool for a mechanic." The manual he "couldn't afford" might have guided John into using diagnostic methods rather than parts swapping.
Diagnosis often requires special tools, like multimeters, feeler guages, compression guages, as well as a basic set of hand tools to manipulate screws, bolts, etc. Many manuals offer instructions in the use of those tools, and if they don't the library is full of instruction manuals on the use of electrical testing equipment.
Finally, logic. Troubleshooting is the process of eliminating potential suspects. All you have to do is devise a question (test) that will demonstrate that the possible suspect (or group of suspects) "aint broke", so don't fix 'em.
Test your ability to think diagnostically.
My factory makes ball bearings. In Quality Control, batches of 27 balls are weighed by an automatic machine. If there is a ball with a bubble in it in the batch it will be light, and the machine diverts them to Sally's work station. Sally is an employee who has been trained to use a balance scale. Your job is to devise a procedure for her to use to identify the light ball without fail in as few steps as possible. Ignore the possibility that there are more than one light ball.
If you can do it in three steps you are in good shape. If not, you need to work on your "divide and conquer" strategies.